Hey everyone my truck starts hard sometimes. It cranks longer then when it takes off it's idled down so low and then it finally takes off. Sometimes I have to crank it a second time and then it'll fire up. I noticed it only does it when I drive my truck ahwile and then let it sit about an hour or two. If you let it sit a day or more it will start fine. Or if you start it right after driving it awhile, it'll start fine. Just after it sits a couple hours it'll do it. What could this be?? Thanks everyone for any answers. It's a 2006 f150 with the 5.4 v8.

 

Could be leaky fuel injectors. Hold your foot to the floor when cranking it, if it fires right up this is what it probably is. Better get that fixed before it hydrolocks.

 

@glc I agree with your assessment of the probable cause - and the procedure. Just to elaborate, in case the OP is unfamiliar with the "de-choke function", it shuts off both injectors AND cops to expel excess fuel from cylinders with fresh air. But it's not going to 'start right up' until he lets off the throttle after de-choke (cranking under WOT). That should confirm the diagnosis - especially well if it idles more smoothly then.